1. Field of the Invention
The present invention relates to a magnetic tape cassette for the VHS system used mainly in a VHS type magnetic tape recorder.
2. Description of the Prior Art
FIGS. 1-3 illustrates the conventional magnetic tape cassette wherein reels (4), (5) for winding a magnetic tape (3) are held inside the casing assembly formed by an upper half casing (1) and a lower half casing (2). Tape guides (6), (7) and (8) for guiding the magnetic tape (3) and a tape pad (9) is provided in the running passage of the magnetic tape between the reels (4), (5) in the front of the casing assembly so that the magnetic tape (3) runs between the reels (4), (5) while it is successively brought into contact with these parts (6) to (9). The front portion of the casing assembly as a running area for the magnetic tape (3) is covered by a guard panel (10) which is pivotally supported by the upper half casing so as to be capable of opening and closing.
When the magnetic tape cassette is put in a video deck, the guard panel (10) is turned upward on the upper half casing (1) so that the running surface for passing the magnetic tape (3) is exposed in front of the casing assembly. Then, a drawing device of the video deck is inserted from the lower half casing side into a head receiving portion (A) formed in the middle of the casing assembly so as to pull out the head, so that recording and reproducing of images can be attained. In the conventional tape cassette, the head receiving portion (A) in the lower half casing (2) is formed by cutting the casing so as to form a channel, whereas the head receiving portion (A) in the upper half casing (1) is formed, as shown in FIG. 2, in such a manner that the projecting plate (13) extending from a bottom plate (12) is formed outside a peripheral rib (11) so as to cover the rotating head.
In the conventional tape cassette, however, the thickness t.sub.1 of the projecting plate (13) outside the rib (11) is smaller than the thickness t.sub.2 of the bottom plate (12) inside the rib (11) as shown in FIG. 3. Therefore, in the resin molding for the upper half casing (1), fine bubbles remained in the thinner projected plate (13) in a plane form to cause white cloudy pattern and deterioration of the appearance and quality.